Stating that KiCAD isn't required

[s39674]

Is your feature request related to a problem? Please describe.

The documentation says: "To give SKiDL some part libraries to work with, you'll also need to install KiCad."

skidl/docs/index.html

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you'll also need to install <a href="http://kicad-pcb.org/">KiCad</a>.

But If I just download the library from: https://gitlab.com/kicad/libraries/kicad-symbols and point the environment variable to it, skidl works fine.

Describe the solution you'd like
I would like the documentation to state that there is an alternative to downloading KiCAD if you just want the libraries.

Additional context
Also, those links are broken:

skidl/docs/index.html

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<p>First, let's look at a "normal" design flow in <a href="https://kicad-pcb.org">KiCad</a>:</p>

skidl/docs/index.html

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you'll also need to install <a href="http://kicad-pcb.org/">KiCad</a>.